Molecular characterisation of Galba truncatula, Lymnaea neotropica and L. schirazensis from Cajamarca, Peru and their potential role in transmission of human and animal fascioliasis

Abstract

BackgroundHuman and animal fascioliasis is emerging in many world regions, among which Andean countries constitute the largest regional hot spot and Peru the country presenting more human endemic areas. A survey was undertaken on the lymnaeid snails inhabiting the hyperendemic area of Cajamarca, where human prevalences are the highest known among the areas presenting a "valley transmission pattern", to establish which species are present, genetically characterise their populations by comparison with other human endemic areas, and discuss which ones have transmission capacity and their potential implications with human and animal infection.MethodsTherefore, ribosomal DNA ITS-2 and ITS-1, and mitochondrial DNA 16S and cox1 were sequenced by the dideoxy chain-termination method.ResultsResults indicate the presence of three, morphologically similar, small lymnaeid species belonging to the Galba/Fossaria group: Galba truncatula, Lymnaea neotropica and L. schirazensis. Only one combined haplotype for each species was found. The ITS-1, 16S and cox1 haplotypes of G. truncatula are new. No new haplotypes were found in the other two species. This scenario changes previous knowledge, in which only L. viator (= L. viatrix) was mentioned. Galba truncatula appears to be the most abundant, with high population densities and evident anthropophyly including usual presence in human neighbourhood. Infection by Fasciola hepatica larval stages were molecularly confirmed in two populations of this species. The nearness between G. truncatula populations presenting liver fluke infection and both human settings and schools for children, together with the absence of populations of other lymnaeid species in the locality, suggest a direct relationship with human infection.ConclusionsThe geographical overlap of three lymnaeid species poses problems for epidemiological studies and control action. First, a problem in classifying lymnaeid specimens in both field and laboratory activities, given their transmission capacity differences: G. truncatula mainly involved in transmission to humans, L neotropica typically responsible for livestock infection, and L. schirazensis unable for transmission. Although several phenotypic characteristics may be helpful for a preliminary specimen classification, a definitive classification can only be obtained by marker sequencing. Aditionally, L. schirazensis increases the confusion, owing to its ability to mix with other Galba/Fossaria species and distort fascioliasis data such as transmission capacity and infection susceptibility. Second, a problem for epidemiological analysis, surveillance and control by methods as mathematical modelling and Remote Sensing - Geographical Information Systems. In Cajamarca, low resolution mapping may be insufficient, as already verified in Andean areas where different lymnaeid species overlap.

New record forGalba neotropica(d'Orbigny, 1835) in Argentina, with a detailed analysis of its morphology and molecular characteristics

“…In agreement with Bargues et al (2012), we believe that without the molecular analyses, the specimens studied in this work would be erroneously identified as G. viatrix or G. cubensis. In Mendoza province G. neotropica was first identified as G. viatrix based on the morphology of the shell and the internal organs, and then correctly identified by using COI sequences (Standley et al 2013).…”

“…1). In Peru it was found in Lima (type locality) and Cajamarca (Bargues et al 2007(Bargues et al , 2012; in Venezuela it was found in Carabobo and Falcón (Bargues et al 2011) and in Argentina it was found in Mendoza, northern Patagonia (Mera y Sierra et al 2009;Standley et al 2013) and Buenos Aires, Central region (Sanabria et al 2012). Identities of all these records were achieved by molecular markers.…”

“…rDNA ITS-2: Galba viatrix ventricosa (AM412224) (Bargues et al 2007); Galba viatrix (HQ283265) (Correa et al 2010); Galba viatrix (JN614465) (Correa et al 2011); Galba neotropica (AM412225) (Bargues et al 2012); Galba cubensis (HQ283264) (Correa et al 2010); Galba cubensis (JN614464) (Correa et al 2011); Galba cubensis (JN614462) (Correa et al 2011); Galba cubensis (JN614463) (Correa et al 2011).…”

CIAS detection of Fasciola hepatica/F. gigantica intermediate forms in bovines from Bangladesh

“…Fasciola gigantica is transmitted by lymnaeids of larger size of the Radix group (Bargues and Mas-Coma, 2005). The presence of lymnaeid vectors defines not only the distribution of fascioliasis, but may also explain the distribution of human infection within a country, as has been recently observed in different countries (Artigas et al 2011;Bargues et al 2011b, c), and within an endemic area, as well as its seasonality or permanent transmission (Bargues et al 2012). In southern Asia, G. truncatula is restricted to the highlands in countries such as Afghanistan and Pakistan (Kendall, 1954(Kendall, , 1965 and its absence as well as the lack of appropriate Galba/Fossaria lymnaeid species for the development of F. hepatica in India and eastward up to South-east Asia is well known (Mas-Coma et al 2009a).…”

Natural infection with Fasciola hepatica (Linnaeus, 1758) in the European bison (Bison bonasus) in Białowieża National Park, Poland

“…It can be assumed that liver fluke is European origin, with the snail Limnaea truncatula as the original intermediate host. Some authors suggest the potential of this wild host in the fascioliasis transmission (Bargues et al, , 2012Khoubbane et al, 2004;Mas-Coma et al, 2009). The liver fluke Fasciola hepatica plays an important role as a parasite of wild and farm animals.…”